A researcher wants to assess if there is a difference in the average age of onset of a certain disease for men and women who get the disease. Let μ1 = average age of onset for women and μ2 = average age of onset for men. A random sample of 30 women with the disease showed an average age of onset of 83 years, with a sample standard deviation of 11.5 years. A random sample of 20 men with the disease showed an average age of onset of 77 years, with a sample standard deviation of 4.5 years. Assume that ages at onset of this disease are normally distributed for each gender, do not assume the population variances are equal. What are the appropriate null and alternative hypotheses?
A) μ1 = μ2 and Ha: μ1 ≠ μ2
B) μ1 ≠ μ2 and Ha: μ1 = μ2
C) μ1 = μ2 and Ha: μ1 < μ2
D) μ1 = μ2 and Ha: μ1 > μ2